Dental process and apparatus



Jan. 22, 1963 D. w. MOORE 3,074,168 DENTAL PROCESS AND APPARATUS Filed May 4, 1961 INVENTOR J4 Via) ifZ/Zval';

ATTORNEYS United States Patent Office 3,674,1d8 Patented Jan. 22, 1963 3,074,168 DENTAL PROCESS AND APPARATUS David W. Moore, 564 Medical Arts Bldg, New Orleans, La. Filed May 4, 1961, Ser. No. 107,800 3 Claims. (Cl. 32-32) This invention relates to a method of and apparatus for dental restoration.

The replacement of lost teeth presents to the dentist, a series of interrelated problems. The existing solutions leave something to be desired, particularly when it is inconvenient for the patient to make repeated visits for the adjustment of the restoration. This invention aims to secure upon the first fitting of the restoration, a replacement sufi'iciently satisfactory so that there will be no need for the patients return to accomplish additional adjustment;

1 It is a common practice in the art of dental restoration to obtain plastic impressions of the upper and lower arches, followed by the casting of positive reproductions of the dental structure in a plaster-like material referred to as stone. The stone reproductions are then mounted in a hinged structure known as an articulator for the purpose of simulating the movement of the patients own teeth in his jaw structure.

The simpler articulators are hinged along a fixed axis passing at right angles through the central plane of the individuals head. Tooth reproductions so mounted are said to be mounted for centric occlusion. Actually, such a mounting is understood to be unrealistically incomplete but it does have the advantage of realistically reproducing one particular mouth condition. A restoration based upon this type of articulation would require extended cut-and-try fitting, after having been placed in the mouth.

The difliculty involved in this approach arises from the fact that the hinge action of the articulator does not accurately simulate the motion of the human jaw. In addition to the primarily pivotal suspension of the human jaw, there is a compound-front-to-back and side-toside movement resulting in what is called briefly, the functional bite. Improved articulators have been devised, designed to reproduce these natural jaw movements to thereby obtain a more refined restoration. However, it is obvious that the measurements and jaw movements of individual patients are such that it is not practical to take all of them into account. It follows that there is a probability that some fitting will be required, in spite of the use of these improved articulators.

The method of the present invention is intended to obtain a restoration requiring a lesser number of visits of the patient to his dentist. After preparation of the mouth structure a single visit is required and it need only be of short duration, sufiicient to satisfy the dentist that his work is complete and satisfactory. The method relies upon exact reproduction of certain of the mouth structure and is not dependent upon attempts to duplicate jaw movement in a compound articulator.

The invention includes a new articulator having a single lower luting bow and a pair of upper luting bows, arranged so that either may be arranged in operative association with the lower luting bow.

For a fuller understanding of the apparatus of my invention, reference should be had to the drawing forming part of this invention wherein:

FIGURE 1 is an isometric elevation of my improved articulator with one of the upper luting bows in operative association with the lower luting bow and the second upper luting bow swung partly out of the way;

FIGURE 2 is a plan view corresponding to FIGURE 1, with a small portion thereof partly in section;

FIGURE 3 is a side elevation corresponding to FIG- URES l and 2, with one of the upper luting bows partly broken away;

FIGURE 4 is a sectional front elevation, taken along the line 44 of FIGURE 2, on a somewhat larger scale than that of the other figures; and

FIGURE 5 is a fragmentary, exploded plan view, partly in section of the upper right portion of FIGURE 2.

The method of the invention can be more readily understood with the aid of the sequence chart of steps which follows:

Upper and lower tooth groups (one group needing restoration) Positive re IllOdllCtlOllS Negative functional impression Mount for centric articulation Remove opposing positive I Seat negative functional on unrestored positive I Form positive opposing group functional of on articulator Remove pos. and neg. functionals-)Neg.

. Pos. Return oppo sing positive I Exchange opposing positives Refine pattern Construct restoration The invention will be explained in terms of the replacement of a lower, front molar with an artificial restoration. It may be assumed that a crown will be required on the second molar and a three-quarters crown on the second bicuspid, if these conditions do not al ready prevail. Initially, an impression is taken of the upper and lower jaws in a manner well known to the art, using preferably an alginate colloid composition. From these impressions, positive reproductions of the two arches are cast in dental stone.

The positive reproductions may then be mounted upon the articulator that I have devised.

The articulator consists of a base member 12 having a lower luting bow 14 extending forwardly from a central body 16. The body 16 includes at its rear, a central support 18 and at its sides, a pair of side supports 20 and 21. The pair of upper luting bows 22 and 23, instead of a single bow distinguishes my articulator from the prior art. Each bow is supported between one of the two respective side supports and a portion of the central support. The front portion 24 or 25 of the respective bows 22 and 23 lies directly above the bow 14, when in operative position. The rear portion 26 of bow 22 forms 3 a broad obtuse angle with the front portion 24, to permit pivoting of the member 22 between its two supports 18 and 20. 7

Although members 12, 22 and 23 are plate-like in character, they must be of sufficient size to aflord the needed rigidity to permit reliable fitting. They may be cast of brass or other suitable non-corrosive material or stamped from heavy plate. Pivotal movement of the upper plate 22 or 23 is accomplished by means of a pair of bearing sockets 28 set in the side edges of the bow 22 at the rear thereof. One of these cooperates with the pin 30 in the central frame support while the other receives the screw pin 32, which is threaded through side frame support 20. The screw pin 32 is manipulated by knurled head 34 and, after suitable adjustment, may be fixed against further movement by means of knurled nut 36.

It will be immediately apparent from an inspection of the drawing, especially FIGURES 1 and 2, that either of the upper bows 22 and 23 may be positioned over and in alignment with the lower bow 14, but both cannot occupy this position at the same time.

Incisal stay rods 38 and 39 adjustably support the forward ends of bows 22 and 23 upon the forward end 40 of the lower bow 14. For adjustment purposes, the stay rods 38 and 39 pass through collars 42, formed on the forward ends of the upper bows, and are adjustably held with the aid of thumb screws 44.

Slots 46 in the luting bows are provided for fixing the stone reproductions or other modeling materials to the bows. If desired, as is well known in the art, separate luting plates may be employed, in which case, fastening devices may be passed through the slots 46 to secure the plates to the bows.

Obviously, numerous modifications, consistent with the known articulator art, may be made in the apparatus herein set out. That which has been described is satisfactory for the practice of the method of my invention.

When the positive reproductions in stone have been completed they are attached to the articulator in conventional manner by embedding the rear surface of the respective stones in plaster, in such manner as to also envelope substantial parts of the appropriate luting how. The upper set of teeth may be secured to either one of the bows 22 or 23. The relationship of the upper and lower sets of reproductions is that of the normal closed bite or centric articulation.

In addition to the two reproductions previously discussed, another specialized impression is required of the general area where restoration is to take place. A splint is prepared of suitable plastic material extending across the area of restoration and seated thereon. A suitable plastic may be one that, after setting, has a higher melting point than the so-called soft dental wax which becomes relatively plastic at the temperatures within the patients mouth. The splint will be formed so that the surface facing the arch not requiring restoration, is well below the normal contact level. The purpose of this splint is to evenly distribute to the jaw structure, the closing force a about to be described. The splint is placed in the patients mouth and upon the surface is placed a layer of soft dental wax, sufiicient to establish contact with the opposing teeth, when the jaws are closed. An impression is then taken of the paths of the cusps of the opposing teeth, traced when the jaws are moved from side-to-side and forward-to-back, while the jaws are in closed position. The functional bite thus obtained shows the functional path traveled by the cusps of the opposing teeth through all of the functional movements of the lower jaw. Although the functional negative impression can be obtained directly from the patients month without first formation of any splint upon the stone reproduction, the detailed procedure is more comfortable to the patient and thus insures a larger. degree of success in obtaining an accurate tracing of the desired tooth paths.

The mounted reproduction of the upper arch, containing the models of the opposing teeth, is swung out of position until again required. The splint and negative impression is then seated upon the lower model in the same relative position it occupied in the mouth. Then the empty luting bow is swung into position. Using special care to obtain all the needed details, plaster or dental stone is worked into the wax functional impression to give a positive functional impression of at least all of the involved area of the upper arch and this positive is united by means of plaster to the second upper bow. When this is properly and securely set, the second bow is swung out of the way and the splint and negative impression are removed from their place on the lower set of reproductions.

Utilizing existing techniques, there is formed on the lower set of reproductions, with the aid of the upper set of reproductions as articulated from the first upper how, a carved wax pattern of the intended restoration. The upper reproduction, articulating with the tentative wax pattern establishes the clearance needed for the teeth with the mouth at rest.

The first upper articulator arm with its full reproduction, is once more swung out of the way to allow the functional positive to come into use. Any interference which might be encountered were the tentative restoration installed as is, will become apparent as the second upper articulator arm is closed. Preferably, a thin layer of indicator paint is applied to the functional casting, in a color contrasting with the carved wax pattern.

Upon closing the second arm into place, a small amount of the indicator paint will be transferred to the wax pattern where there is interference. Interfering spots may be carved away in accordance with the indication developed. By repeating these operations as necessary, the carved wax pattern will be free of any interference caused by the functional movements of the jaw as well as having been formed to satisfactorily perform its intended duty during simple, normal operation of the jaw.

From the wax pattern thus constructed, a suitable restoration may thus be produced of suitable metal, with or without resort to an artificial porcelain replacement for the missing tooth, all utilizing standard procedures, well known in the art. It will be apparent that although I have disclosed the invention in connection with the replacement of a single lower molar, the elements of the invention may be rearranged to provide for other restorations as well.

Because I have provided a method and apparatus for accurately articulating two diiferent reproductions of the same dental structure with a single reproduction of the corresponding dental structure, I have made it possible to produce a restoration that, when fitted in place, works effectively with the natural teeth, both at rest and in functional use. It will be obvious that a faithful restoration with all traces of interference removed, will perform effectively and without trouble.

The words, steric hinderance, used herein refer to the inability of two solid bodies to occupy a single given space at one time. Thus, the elements 22 and 23 constitute sten'c hinderances one to the other in operative position.

Inasmuch as alternate methods are known for mounting, taking impressions and casting reproductions, are well known in the art, the appended claims are intended to define the whole scope of the invention without limitation as to the preferred mode of practicing the invention as disclosed above.

I claim:

1. A dental articulator including a base, a lower mounting thereon for securing rigidly a reproduction of elements of a human lower jaw structure, an upstanding support member arranged generally rearwardly and to one side of said base, an upper mounting for securing rigidly a reproduction of elements of a human upper jaw structure, means securing said upper mounting to the support for pivotal movement of the upper jaw elements toward and away from the lower jaw elements in normal centric occlusion and a second upper mounting for securing rigidly a reproduction of elements of a human jaw structure, a second upstanding support member arranged generally rearwardly and toward the side opposed to said first support member, means securing said second upper mounting to the second support for pivotal movement of its upper jaw elements toward and away from the lower jaw elements, each of said first and second mountings constituting a steric hinderance to the other when the respective upper jaw elements are in place and each of said first and second mountings being removable from occulsal position to permit the other said mounting to occupy said occlusal position.

2. The articulator of claim 1 including a forwardly extending portion on the base to serve as a datum point, a pair of rod-like stay members, and means on each of the upper mountings for adjustably securing one of the stay members with respect to the datum point to align the respective upper mountings with the lower mounting.

3. A dental articulator including a base, a lower mounting thereon for securing rigidly a reproduction of elements of a human lower jaw structure, a pair of upstanding support members arranged generally rearwardly of said base, an upper mounting for securing rigidly a reproduction of elements of a human upper jaw structure, means securing said upper mounting between the support members for pivotal movement of the upper jaw elements toward and away from the lower jaw elements in normal centric occlusion, a third upstanding support member arranged rearwardly of said base, and a second upper mounting for securing rigidly a reproduction of elements of a human jaw structure, means securing said second upper mounting between the third and one of the first two supports for pivotal movement of its upper jaw elements toward and away from the lower jaw elements, each of said first and second mountings constituting a steric hinderance to the other when the respective upper jaw elements are in place and each of said first and second mountings being removable frorn occlusal position to permit the other said mounting to occupy said occlusal position.

References Cited in the file of this patent UNITED STATES PATENTS 2,029,003 Spiro Jan. 28, 1936 2,238,551 Bloom Apr. 15, 1941 2,758,374 Fisher Aug. 14, 1956 2,909,837 Gerber Oct. 27, 1959 2,930,127 Mann Mar. 29, 1960 

1. A DENTAL ARTICULATOR INCLUDING A BASE, A LOWER MOUNTING THEREON FOR SECURING RIGIDLY A REPRODUCTION OF ELEMENTS OF A HUMAN LOWER JAW STRUCTURE, AN UPSTANDING SUPPORT MEMBER ARRANGED GENERALLY REARWARDLY AND TO ONE SIDE OF SAID BASE, AN UPPER MOUNTING FOR SECURING RIGIDLY A REPRODUCTION OF ELEMENT OF A HUMAN UPPER JAW STRUCTURE, MEANS SECURING SAID UPPER MOUNTING TO THE SUPPORT FOR PIVOTAL MOVEMENT OF THE UPPER JAW ELEMENTS TOWARD AND AWAY FROM THE LOWER JAW ELEMENTS IN NORMAL CENTRIC OCCLUSION AND A SECOND UPPER MOUNTING FOR SECURING RIGIDLY A REPRODUCTION OF ELEMENTS OF A HUMAN JAW STRUCTURE, A SECOND UPSTANDING SUPPORT MEMBER ARRANGED GENERALLY REARWARDLY AND TOWARD THE SIDE OPPOSED TO SAID FIRST SUPPORT MEMBER, MEANS SECURING SAID SECOND UPPER MOUNTING TO THE SECOND SUPPORT FOR PIVOTAL MOVEMENT OF ITS UPPER JAW ELEMENTS TOWARD AND AWAY FROM THE LOWER JAW ELEMENTS, EACH OF SAID FIRST AND SECOND MOUNTINGS CONSTITUTING A STERIC HINDERANCE TO THE OTHER WHEN THE RESPECTIVE UPPER JAW ELEMENTS ARE IN PLACE AND EACH OF SAID FIRST AND SECOND MOUNTINGS BEING REMOVABLE FROM OCCULSAL POSITION TO PERMIT THE OTHER SAID MOUNTING TO OCCUPY SAID OCCLUSAL POSITION. 